Delay cap



April I so,` 1935.

H. E.y NASH DELAY CAP Filed Maron 22, 1952 Patented Apr. 30, 1935 l UNITED ASTATI-:s

4PATE DELAY CAP -Henry E. Nash, Wilmington,

Hercules Powder Company,

Del., assigner to Wilmington, Del., a

corporation oi' Delaware Application March 22, 34 Claims.

My invention relates to an improvement in delay caps such as are used for detonating explo.

sives when it is desired to detonate several charges successively by means of caps simulta- 5 neously ignited.

Heretofore delay caps have Icomprised essentially a detonating charge, anigniter charge and a fuse through the medium of which the detonating charge is fired, the fuse being cut to such length as will afford desired delay between the ring of the igniter charge and the ring of the detonating charge which effects detonation of the explosive to be detonated. In such caps, as heretofore produced, the ignition elements have been `'.5 encased in a metallic casing suitably plugged and provided with a vent hole or passage for the escase of gases evolved in the urning of the igniter charge an fuse, the vent h le or passage .being customari y closed by means of a irangible material, or materialV which will not offer a substantial obstruction to the escape of the gases after the fuse is iired.

In delay caps as heretofore produced the provision of a vent has been essential, since a large quantity of gas is rapidly developed in the burn- :ing of the igniter charge and i'use, which if not permitted to freely escape from the casing would develop high pressure, which, among other deleterious effects, would cause acceleration of the burning rate of the fuse and consequently premature detonation of the explosive. However, on the other hand, the provision of a vent is objectionable and disadvantageous since the vent however carefully closed, without negation of its func-A tion, aords a possible course for the entry of water or moisture into the interior of the casing. Further, premature fignition of the explosive may occur through co tact therewith of hot gases from the burnin of the. fuse which escape thrqugh the vent, and irregularity in the burning of the ruse may occur through improper venting or accidental stoppage of the vent which will ,result in a building -up of pressure within the casing. l ,Y Now, in accordance with my invention I provide a delay cap of such a-character that the necessity for a vent is obviated and consequently in which the igniter charge fuse and detonating charge 'may be sealed within e casing and positively protected from moisture, and atfthe sam'e time risk of premature detonation di the ex-v plosive through acceleration of the burning ra'te of the fuse or ignition of the explosivev from contact with Aa flame vnr hot gases trom the delay 55 cap is positively eliminated.

1932, serial Nq. 600,449 (ci. 1oz-1o) In accordance with 'my invention I provide boardly a ventless cap, and more particularly a ventless cap furnished with a fuse, and desirably also with an igniter charge, of such a character that on burning no substantial quantity of 5 gas will be evolved, or, where the character of the fuse and/or igniter charge is such as to kevolve any substantial amount of gas on burning, I provide means within the cap for absorbing evolved gas to an extent such as to avoid delel0 terious pressure within the cap. I

In the practical adaptation of my invention where it involves the use of a fuse of such character that it will not evolve any substantial amount of gas on burning, I form the fuse, and `u; desirably also the igniter charge, from a mixture of an oxidizing agent and a substance which when burned in the presence of the oxidizing agent will reacttherewith without producing any substantial quantityl of reaction product in gas- 20 ecus form.

As illustrative of one practical embodiment of. my invention, I may, for example, form the powder charge of the fuse, and desirably also the igniter charge, from a mixture of an oxidizing agent, as, for example, barium peroxide, potassium chlorate, potassium permanganate, red lead (Pba04) or the like, which ay be included in amount within say the r ge 50%-98%, by weight, and, for example, one or more of the elements of the right hand column of group VI of the periodic table, i. e sulphur, selenium, or tellurium, which may b vincluded in amount Within say the range 2%-50%, and to which, if desired, may be added, for example, anvinert material as barium oxide, magnesium oxide, lead oxide (PbO), or the like, in amount within say the range 1%-30%, which will exert a control on the rate of burning of the mixture.

Where a metallic oxide-is used as ythe oxidizing agent, it is preferably used in such excess that a .solid salt of the metal and the Oxy-acid radical formed by the oxidation of the oxidizable element is obtained. For example, using BaO: `or PbaOi and sulphur, BaSO4 or PbSO4. would-re- 45 sult, together, of course, with BaO and PbO.

As illustrative of another practical embodiment of my invention, Imay'form the powder charge of the fuse and also the igniter charge of any suitable materials used for such purposes, using desirably materials which on burning will evolve a minimum of gas, for example, the materials as hereinbefore described may be used, and place within the cap, in a chamber provided therefor adjacent to the ignition end of the fuse, a

A charge, as mercury a substance such as silica gel, activated charcoal, or the like, which will act to absorb gas evolved in the burning of-an ignition charge and fuse of suitable composition, as for example, potas-v sium chlorate and selenium, to an extent such that no material or deleterious pressure will be developed within the cap.

By way 'of more speciiically illustrating theA practical embodiment of my invention, when the powder charge of the fuse and the ignition charge are of such character that on firing no substantial amount of gas will be evolved, ref.- erenoe is made to the accompanying drawing, in which:

Fig. l is a vertical section through a delay cap embodying such features of the invention; and

Fig. 2 is a fragmentary similar vertical section through a modiiication.

In the drawing A indicates a casing, preferably of metal as, forexample, copper. At the bottom of the casing is positioned a'detonating charge B, formed, for example, of mercury fulmlnate or other suitable primary detonating material, or4 the detonating charge maycomprise a primer fulminate, or the like, and a base charge, such as tetryl, or the like. Above the detonating charge is positioned a fuse C,'consist ing of a fuse powder d, comprising a mixture of, for example, 15% selenium and 85% barium peroxide, within a metal Acontainer e about which there lmay be, if desired, a mapping of cloth, or other suitable material f., It will be understood that the length of the fuse C will be made such as to give `the desired delay in ring of the detonating charge B after ignition of the fuse.

Above the fuse and for the purpose of ignitng it, there is positioned a sulphur plug G provided with a recess iilled with an igniter charge H, desirably having the same characteristics as that of the fuse powder d and if desired of a similar composition. Above the sulphur- Vplug C is a waterproong material I of any desired compositionandthe casing Aisclosedatthetopbymeans. of a sulphur plug J, which when p oured enters f the crimp Ic 'and becomes keyedto the casing.

' means are provided Lead wires 1n., l I Y through plug J, the waterproofing composition I.,

vthe plug G and into the igniter charge H. The

ends of the lead wires are connected by means of a bridge wire n, as is'usual in cap construction, and the bridge wire may, if desired, be coated with a readily ignitible composition as, for example, diazodinitrophenol and potassium chlorate, or the like, with a binder as, for example. nitrocellulose or the like, the'binder being in quantity,however, insuillcientto produce any substantial quantity o! gas on burning.v

By way of more specically illustrating the practical embodiment of my invention where to absorb gaseous reaction products which may be evolved, reference is made to the accompanying drawing, vFlgu1e'2 .whicli is a sectional view of a cap embodying my invention, the upper and lower portions being broken away. 1n the c'ap illustrated by `Figure 2, A indicates the casing, H the igniter charge, n the bridge wire, m, 1n the lead wires end e the fuse,

4wrapped as indicated at f, and a powder charge a of any mutable composiuaiisthat is to say, onewhich will not give of! an excessive amoimt oi gas. Desirably, for example, -the chargemay be composed or potassium chlorate m extend into the casing A'.

and selenium. G indicates a sulphur plug which connes the igniter charge and in which is formed a passage q opening into a chamber in the casing above the plug G'closed at its top by a plug L, which prevents entry of the waterproof sealing material I. The chamber' is lled with absorbent material o, which may be silica gel, activated carbon, or anabsorbent material which .will chemically react with the evolved vapors to produce a-solid. Ii desired, the passage q may be eliminated when the plug G is made a loose nt in the casing.

As further illustrative of a practical embodiment of my invention, the fuse, and/or the igniter charge may comprise a mixture of red lead and sulphur,in various proportions, say for example 85%-98% red lead and 2%l5% sulphur, and to which if desired may be added an inert material or 'an active oxidizing material to decrease or increase the burning rate. A satisfactory composition may for example'involve red lead 97.2% and sulphur 2.8%, the ingredients being suitably ground by being mixed together, water added to form avpaste, the paste ground in a ball mill and then dried in a current of warm air. The cake formed on drying of the paste4 is broken up and heated at an elevated Vtemperature, say 1Z0-130 C., to harden the powder and render it suitable for graining, say for one and one half hours. It willbe appreciated that the temperatures and time used in hardening the powder may be widely varied. As has been indicated the powder may contain an inert substance or an oxidizing agent in addition to red lead and sulphur. Thus, for example,'a satisfactory powder is comprised of red lead 91%. sulphur 3% and lead oxide (litharge) 6%. The red lead and sulphur composition will on burning produce a minimum of gas and at the same time will have the advantages of substantial resistance to moisture and a iixed burning rate. Selenium or tellurum may be substituted for sulphur in the combination with red lead.

The operation of the delay cap invaccordance with my invention will, it is believed, be obvious,

itbeing understoodvthat on closing an electric circuit through the lead wires m, m the bridge wire n will be highly heated or fused, the ignite'r charge H will be ignited and will ignite the fuse C, which von vburning 'down to .the detonating charge B will iire it for the detonation of an explosive charge with which the cap is assoelated. When the powder charge of the fuse and the 'igniter charge are such as not to evolve amr substantial amount of gas on burning, the cap is arranged as shown in Fig. 1. On the other hand, if it is desired to use a powder charge and an igniter charge of such a composition as will evolve a substantial amount of gas, the cap will contain an absorbent material, as shown in Fig'. 2'

and the evolved gas passing through the passage q, or by plug G will be sufficiently absorbed by the abwrbent material as to avoid the development' of deleterious pressure within the cap.

It will be noted that the cap embodying my invention is not provided with any vent, the charges t and fuse being conilnedwlthin the casing vand positivelyprotected, and it will be noted that in the burning of theignltion charge and ofthe duse no substantial evolution of gas will occur due to the composition of the powder comprised in the chargeand'fuse, or that it in the case of any suitablecharge any substantial amount o! gas is' evolved, it will be absorbed with, avoid anceof deleterious pressurewithin the cap.

It will-be furtherunderstood that I contemplate my invention as applicable. to delay igniters as well as to delay caps in connection with rwhich, more particularly, I have described my invention herein. When the invention is applied to a delay igniter, for the ignition oi', for example, black powder, as will be obvious the structure illustrated and described herein will be modied to the extent that a match composition,Y consisting, for example, of black powder, fulminate chlorate charcoal nitrostarch mixture, or the like, will be substituted for the detonating charge B and the bottom of the casing A will be left open, the 'match composition being protected from moisture by a coating of lacquer or other suitable waterprooilng., Hence, it will be understood that I contemplate adelay igniter. as the equivalent'of a delay cap and as within the scope of the `claims appended hereto, in which the term a detonating charge will be understoodtofinclude a match composition or igniter. It will be understood that Ido notintend my invention to be limited by the specification ot particular `compounds or compositions herein,

, nor to the cap structure described herein for purposes ot illustration, since I- contemplate as within the scope oi' my invention the use oi' any compound or composition operably equivalent for those specified, and where an absorbent is used,

I contemplate vthe use" oi any absorbent or adsorbent material or other means for avoiding the development of vdeleterious gas pressure within a cap, and of any suitable charging composition. Further, it 'will-be understood that I do not limit the application of my inventionl to a cap the casing of which is ventless, sincefun- -der conditions the casing may be desirably vented. as for example,v vented'more or, less for the escape of any excess gas developed or not absorbed by the` absorbent material.

I have not claimed herein the-fuse composition described.' Such, however, forms the subject matter of an application Serial No. 542,576, iiled June 6, 1931, filed by me as a division of the application Serial No. 440,696 iiled April l, 1930 oi' which this application is a continuation in part.

What I claim and desire to protect by' Letters Patent is:

r-'l A delay carrincluding anfigniter charge. a

detonating charge and a fuse, conned within a rigidly and permanently sealed ventless c aslng the powder train of the' fuse comprising a composition which will burn lwithout' development oi' any substantial amount of gas. l 2. A delay -cap including nently sealed ventless casing. an igniter'charse, gdclonating charge and a fuse and means wherey e sure within the casing Aon burning ofsthe fuse will be avoided. 'f

3. A delay caplncluding a 'rigidly and Dermanently sealed ventlesscasing, an igniter charge, a detonating charge and a ius'e, the fuse including an oxidizing agent and a vsubstance which when burned in the presence agent will react lwithout the 4evolution ofgas in suiiiclent quantity to rupture the. casing or accelerate'the rate of burning o! the fuse.

4. A delay capincluding'a rigidly'and permanently sealed ventless casing, an igniter charge, a

detonating charge and ai the igniter charge and the fuse respectively Aincluding'an voxidizing when burned in the presence oi the oxidiing agent will react a rigidly and .permadevelopment ot any substantial lgas presof the oxidizing.

a detonating charge and a fuse, the ignitercharge and the fuse respectively including an oxidizing agent and an oxidizable material which unite on burningto form a solid residue without the evolution of any appreciable amount of gas.

7. A' delay cap including a rigidly and permanently sealed ventless casing, an igniter charge, a detonating charge and a fuse, the fuse including an oxidizing agent and selenium,

.which unite on burning to form a solidresidue without giving of any substantial amount oi gas. 8. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge, a detonating charge and a fuse, the igniter charge without the evolution of gas in suiiicient quanand the fuse respectively including an oxidizing agent and selenium, which unite on burning to form a solid residue without giving oi any substantial amount of gas.

9. A delay cap igniter charge. a d tqnating charge and a fuse,

luding a ventless casing, auV

the fuse including barium peroxide and selenium.

l0. A delay cap includingv a ventless casing, an igniter charge, a detonating charge and a fuse. the igniter charge and the fuseresp'ectively including barium peroxide and selenium.

ll. A delay cap including a ventless casing, an igniter charge, a detonating charge and a fuse, the fuse including red lead and sulphur.

12. A delay cap including a ventless casing, an igniter charge, a detonating charge and a fuse, the igniter charge and the Ifuse respectivelyvincluding red lead and sulphur.

v 13. A delay cap including a casing, an igniter charge, a detonating charge and a fuse, the fusephur.

14. A delay cap including a casing, an igniter charge, a`detonating charge and a'fuse, the fuse including 97.2% red lead and 2.8% sulphur.

-15. A delay cap including a ventless casing,

an igniter charge, a detonating charge and a' fuse, the fuse including red lead, sulphur and an inert material. u

16. A delay cap including a ventless casing, an

4including 95%-98% red lead and 2%-15% sul- 17. A delay cap including a ventless casing, an

igniter charge, a detonating charge and a fuse,

the fuse including red lead, sulphur and litharge.

18. A delay cap including a casing, an igniter charge, a detonating charge and a fuse, a chamber formed in the casing and adapted to receive gas evolved on burning of the i'use and a gas absorbent material within said chamber.

' 19. A Vdelay cap including a casing, an igniter charge, a detonating charge and a fuse', a chamber formed in the casing and adapted to receive gas evolved on burning oi' the fuse and-silica gel within said chamber.

20. A delay cap'including a casing, an igniter.k

charge. a detonating charge and a fuse, the fuse including an oxidizing agent and an element oi' the right hand column oi' Group VI of the periodic system, a chamber formed in Asaid casing and adapted to receive gas evolved on 'burning of said fuse and a gas absorbent material within said chamber.

21. A delay cap including a casing, an igniter charge, a detonating charge and a fuse, the fuse including an oxidizing agent and an element of the right hand column of Group VI of the periodio system, a chamber formed in said casing and adapted to receive gas evolved on burning oi'said fuse and silica gel within said chamber.

22. A delay cap including a casing, an igniter charge, a detonating charge and a fuse, the fuse including' an oxidizing agent and selenium, a. chamber formed in said casing and adapted to receive gas evolved on burning of said fuse and l a gas absorbent material within said chamber.

23.- A delay cap including a casing, an igniter charge, a detonating charge and a fuse. the fuse including an oxidizing agent and selenium, a chamber formed in said casing and ad'apted to receive gas evolved on burning of said fuse Yand silica gel within said chamber. 3

24. A delay cap including a ventless casing, an igniter charge, a detonating charge and a fuse, the fuse including an oxidizing agent, comprising a metallic oxide, and an element of the right hand column of the sixth periodic group.

25. A delay-cap including a ventless casing, an igniter charge, a detonatingy charge and a fuse, the igniter charge including an oxidizing agent, comprising a metallic oxide, and an element of the right hand column of the sixth periodic group.

26. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge,

a detonating charge and aiuse, the igniter charge and the use respectively including an oxidizing agent and an' element of the right hand column burning without any substantial development of of group VI of the periodic system which when burned in the presence of the oxidizing agent will react without the evolution of ga's in suiiiclent quantity to rupture the casing.

27. In an electrical fuse, a priming pellet and a fuse composition, each comprising a mixture gas;

28. In an electrical fuse, a priming pellet, a fuse compositionand a weatherproof casing surrounding said pellet and fuse composition, said pellet and fuse/composition'each comprising a mixture which upon ignition burns without any substantial development of gas.

29. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge,

a detonator charge and a fuse, the powder train of the fuse comprising in admixture an oxidizing agent, a substance which when burned in the presence of the oxidizing agent will react without the evolution oi gas in suicient quantity to rupture the casing and an inert material which will exert' a control on the rate of burning .of the mixture. Y

30. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge, a detonator charge and a fuse, the igniter charge and the powder train of the fuse, respectively, comprising a substance which when burned -in the presence vof the oxidizing agent will react without the evolution of gas in sufiicient quantity to rupture the casing and an'inert material which will exert a control on the rate of burning-of the mixture.

3l. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge, a detonator charge and a fuse, the powder train of the fuse comprising in admxture selenium, an oxidizing agent which on burning will react without the evolution of gas in suflici'ent quantity to rupture the casing and an .inert substance which will exert a control on the rate of burning of the mixture.

32. A delay cap including a rigidly and permanently sealed ventless casing', an igniter charge, a detonator charge and a fuse, the powder train of the fuse comprising in admixture selenium, barium peroxide and an inert substance which will exert a control on the rate of burning of the mixture.

33. A delay cap including a rigidly and permanently sealed ventless casing, an igniter charge, a detonator charge and a fuse, the powder train o! the fuse comprising in admxture a substance from the group consisting of sulphur, selenium and teilurium and -an oxidizing agent which when burned with said substance will react without the evolution oi gas in suiiicient quantity to rupture the casing.

34. A delay cap including a rigidly and permanently sealed ventless casing. an igniter charge, a detonator charge and a 4fuse, the powder train of the fuse comprising in admxture a substance from the group consisting f sulphur, selenium and tellurium, an oxldizin agent which when burned with said substance will react without the levolution of gas in suillcient quantity to rupture the casing and an inertsubstance which will exert acontrol on the burning rate of the mixture.

HENRY E. 

